Just wondering but does anyone know how to make houses and stuff buyable? Like benirus manor and stuff?

Ummmm... if you're talking about Oblivion, just stick to the ones that are already for sale...
If you're talking about Morrowind then kill the occupants one by one and pay the fines as you go, or become Grandmaster of a Great House.

But I am trying to make a new house. I know!!! Make a quest and as a reward you get the key to the house so like :New House A Quest: Give me 50 sptims and as a reward you will get this key to the house

ummmm isn't that a little easy?

If you're on a PC you can finish quests by typing in certain commands in the console. So once you've triggered one of the 'Buying a house in...'-quests you can complete them instantly, thus giving you the key (and maybe also take away money, but I'm not sure about this).

Try searching here for more tips.

Do you want to buy a house or create your own, if so just go through the CS. If you just want to buy it, check the counts or countesses, or some others like that.